class_docstr: Binomial variance function
  
  p = mu / n; V(mu) = p * (1 - p) * n
  
  INPUTS:
     n -- number of trials in Binomial
code: def __init__(self, n=1):
      self.n = n
  
file_path: nipy/nipy/algorithms/statistics/models/family/varfuncs.py
imports: import numpy
label_desc: Use image node_id 1 to create a new Binomial object  with example: obj = Binomial(n)